One embodiment of this invention relates to canisters, particularly desiccant canisters. More particularly, one embodiment of this invention relates to a canister containing a cap which is secured upon a body portion of the canister, wherein because of the structure of the canister, there is a reduced risk of “cap pop-off” during manufacturing and use of the canister. The unique structure of the canister more securely affixes the cap to the body portion of the canister than occurs with prior art canisters.
A number of small desiccant canisters formed from gas and liquid impermeable body portions onto which are secured one or more perforated end caps have been disclosed. These canisters generally contain a desiccant material which absorbs moisture from the air as the air flows through the perforations in the end caps of the desiccant canister.
A common structure of these canisters is a one piece plastic body containing a cylindrical outer wall and a circular bottom wall, onto which is secured a cap containing a cylindrical outer wall and a circular top wall. In one embodiment the canister has a snap fit locking system contained in the outer wall of the body and the outer wall of the cap to assist in holding the cap onto the body. One such locking system is disclosed in U.S. Pat. No. 4,093,105, whereby a locking rib (22) in an upper portion of the cylindrical outer wall of the body portion snaps into a recess (32) in an upper cylindrical portion of the cap when the cap is secured onto the body.
Another similar method of securing a cap to a body of a desiccant canister utilizes a locking rib (26) of the body which interacts with a recess (36) in an outer wall of the cap to form a snap fit, as shown in U.S. Pat. No. 5,759,241.
An alternative structure for securing a cap to a body a canister is disclosed by U.S. Pat. No. 5,730,785, whereby the cap, comprising a cylindrical portion (27) with an annular bead (29), fits within a groove (30) of the body. In this structure a portion of the cap extends downward within the body of the canister. This structure contrasts with the structure that is disclosed by U.S. Pat. Nos. 4,093,105 and 5,759,241 wherein the cylindrical outer wall of the cap is secured over an upper portion of the outer wall of the body. To provide additional structural support for the ends of the canister of U.S. Pat. No. 5,730,785, these ends contain ribs (15 and 15′), as shown in FIGS. 3 and 4. These ribs extend from one outside edge of each cap to another outside edge of the cap.
Although canisters, particularly desiccant canisters, have been formulated using designs such as those disclosed hereinabove, problems often occur with the caps popping off of the body during manufacturing and assembly, particularly when horizontal pressure is placed on the body of the canister, or during use of the desiccant canister.
Therefore it is one object of an embodiment of the invention to provide an improved canister, particularly for use with desiccants.
It is another object of one embodiment of the invention to provide a canister which addresses the issue of cap pop-off that can occur during manufacturing and assembly of the canisters.
It is a further object of the invention to provide a design for canisters, particularly desiccant canisters, which contains a structure which is resistant to horizontal pressure placed on the sides of the body of the canister during manufacture or use.
These and other objects and features of one embodiment of the invention will become apparent to those skilled in the art from a consideration of the following detailed description, drawings and claims. However, the description, along with the accompanying drawings, provides only selected example of the construction of the product to illustrate one embodiment of the invention and does not place any imitations on the scope of the invention.